// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_FRAME_HOST_FRAME_NAVIGATION_ENTRY_H_
#define CONTENT_BROWSER_FRAME_HOST_FRAME_NAVIGATION_ENTRY_H_

#include <stdint.h>

#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "content/browser/site_instance_impl.h"
#include "content/common/resource_request_body_impl.h"
#include "content/public/common/page_state.h"
#include "content/public/common/referrer.h"

namespace content {

// Represents a session history item for a particular frame.  It is matched with
// corresponding FrameTreeNodes using unique name (or by the root position).
//
// This class is refcounted and can be shared across multiple NavigationEntries.
// For now, it is owned by a single NavigationEntry and only tracks the main
// frame.
//
// If SiteIsolationPolicy::UseSubframeNavigationEntries is true, there will be a
// tree of FrameNavigationEntries in each NavigationEntry, one per frame.
// TODO(creis): Share these FrameNavigationEntries across NavigationEntries if
// the frame hasn't changed.
class CONTENT_EXPORT FrameNavigationEntry
    : public base::RefCounted<FrameNavigationEntry> {
public:
    FrameNavigationEntry();
    FrameNavigationEntry(const std::string& frame_unique_name,
        int64_t item_sequence_number,
        int64_t document_sequence_number,
        scoped_refptr<SiteInstanceImpl> site_instance,
        scoped_refptr<SiteInstanceImpl> source_site_instance,
        const GURL& url,
        const Referrer& referrer,
        const std::string& method,
        int64_t post_id);

    // Creates a copy of this FrameNavigationEntry that can be modified
    // independently from the original.
    FrameNavigationEntry* Clone() const;

    // Updates all the members of this entry.
    void UpdateEntry(const std::string& frame_unique_name,
        int64_t item_sequence_number,
        int64_t document_sequence_number,
        SiteInstanceImpl* site_instance,
        scoped_refptr<SiteInstanceImpl> source_site_instance,
        const GURL& url,
        const Referrer& referrer,
        const std::vector<GURL>& redirect_chain,
        const PageState& page_state,
        const std::string& method,
        int64_t post_id);

    // The unique name of the frame this entry is for.  This is a stable name for
    // the frame based on its position in the tree and relation to other named
    // frames, which does not change after cross-process navigations or restores.
    // Only the main frame can have an empty name.
    //
    // This is unique relative to other frames in the same page, but not among
    // other pages (i.e., not globally unique).
    const std::string& frame_unique_name() const { return frame_unique_name_; }
    void set_frame_unique_name(const std::string& frame_unique_name)
    {
        frame_unique_name_ = frame_unique_name;
    }

    // Keeps track of where this entry belongs in the frame's session history.
    // The item sequence number identifies each stop in the back/forward history
    // and is globally unique.  The document sequence number increments for each
    // new document and is also globally unique.  In-page navigations get a new
    // item sequence number but the same document sequence number.  These numbers
    // should not change once assigned.
    void set_item_sequence_number(int64_t item_sequence_number);
    int64_t item_sequence_number() const { return item_sequence_number_; }
    void set_document_sequence_number(int64_t document_sequence_number);
    int64_t document_sequence_number() const { return document_sequence_number_; }

    // The SiteInstance responsible for rendering this frame.  All frames sharing
    // a SiteInstance must live in the same process.  This is a refcounted pointer
    // that keeps the SiteInstance (not necessarily the process) alive as long as
    // this object remains in the session history.
    void set_site_instance(scoped_refptr<SiteInstanceImpl> site_instance)
    {
        site_instance_ = std::move(site_instance);
    }
    SiteInstanceImpl* site_instance() const { return site_instance_.get(); }

    // The |source_site_instance| is used to identify the SiteInstance of the
    // frame that initiated the navigation. It is present only for
    // renderer-initiated navigations and is cleared once the navigation has
    // committed.
    void set_source_site_instance(
        scoped_refptr<SiteInstanceImpl> source_site_instance)
    {
        source_site_instance_ = std::move(source_site_instance);
    }
    SiteInstanceImpl* source_site_instance() const
    {
        return source_site_instance_.get();
    }

    // The actual URL loaded in the frame.  This is in contrast to the virtual
    // URL, which is shown to the user.
    void set_url(const GURL& url) { url_ = url; }
    const GURL& url() const { return url_; }

    // The referring URL.  Can be empty.
    void set_referrer(const Referrer& referrer) { referrer_ = referrer; }
    const Referrer& referrer() const { return referrer_; }

    // The redirect chain traversed during this frame navigation, from the initial
    // redirecting URL to the final non-redirecting current URL.
    void set_redirect_chain(const std::vector<GURL>& redirect_chain)
    {
        redirect_chain_ = redirect_chain;
    }
    const std::vector<GURL>& redirect_chain() const { return redirect_chain_; }

    void SetPageState(const PageState& page_state);
    const PageState& page_state() const { return page_state_; }

    // The HTTP method used to navigate.
    const std::string& method() const { return method_; }
    void set_method(const std::string& method) { method_ = method; }

    // The id of the post corresponding to this navigation or -1 if the
    // navigation was not a POST.
    int64_t post_id() const { return post_id_; }
    void set_post_id(int64_t post_id) { post_id_ = post_id; }

    // The data sent during a POST navigation. Returns nullptr if the navigation
    // is not a POST.
    scoped_refptr<ResourceRequestBodyImpl> GetPostData() const;

private:
    friend class base::RefCounted<FrameNavigationEntry>;
    virtual ~FrameNavigationEntry();

    // WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
    // Add all new fields to |UpdateEntry|.
    // TODO(creis): These fields have implications for session restore.  This is
    // currently managed by NavigationEntry, but the logic will move here.
    // WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING

    // See the accessors above for descriptions.
    std::string frame_unique_name_;
    int64_t item_sequence_number_;
    int64_t document_sequence_number_;
    scoped_refptr<SiteInstanceImpl> site_instance_;
    // This member is cleared at commit time and is not persisted.
    scoped_refptr<SiteInstanceImpl> source_site_instance_;
    GURL url_;
    Referrer referrer_;
    // This is used when transferring a pending entry from one process to another.
    // We also send the main frame's redirect chain through session sync for
    // offline analysis.
    // It is preserved after commit but should not be persisted.
    std::vector<GURL> redirect_chain_;
    // TODO(creis): Change this to FrameState.
    PageState page_state_;
    std::string method_;
    int64_t post_id_;

    DISALLOW_COPY_AND_ASSIGN(FrameNavigationEntry);
};

} // namespace content

#endif // CONTENT_BROWSER_FRAME_HOST_FRAME_NAVIGATION_ENTRY_H_
